Add drone config

.drone.yml

@@ -0,0 +1,38 @@
+kind: pipeline
+type: docker
+name: ui
+
+steps:
+- name: build
+  image: node:12.7.0
+  volumes:
+  - name: build
+    path: /build/
+  commands:
+  - yarn install
+  - yarn build
+  - mv build/* /build/
+  when:
+    branch:
+    - master
+- name: upload
+  image: plugins/s3
+  volumes:
+  - name: build
+    path: /build/
+  settings:
+    access_key:
+      from_secret: minio_access_key
+    secret_key:
+      from_secret: minio_secret_key
+    bucket: siteroot
+    source: /build/**/*
+    strip_prefix: /build
+    target: /
+    path_style: true
+    endpoint:
+      from_secret: minio_target
+    
+volumes:
+- name: build
+  temp: {}